Field
The present invention relates to computing devices. In particular, but not by way of limitation, the present invention relates to reducing errors and retaining data in flash memory devices.
Background
In general, a flash memory device is one type of memory device that can retain stored digital data—even when no power is being provided to the device. This nonvolatile memory (for nonvolatile data) is available in many forms including NAND memory.
The data on flash memory degrades overtime, which is known as data decay, and this decay is accelerated by extreme temperatures. When data on flash memory is read over and over again, this can also cause decay of data. This is known as read disturb, which can degrade the data in the page/block that is read and the adjacent cells (e.g., including other pages or blocks) as well.
A known method to handle these aspects of decay/degrade/disturb of the data is to refresh the data (e.g., copying the data from one flash block to another block). This refresh occurs periodically—typically every few months. Traditionally these refresh options end up refreshing all the blocks in the device and are not power-down safe. In the event of a power down, the refresh usually reoccurs on the entire file system partition; thus, wearing the memory down.